A hydrocracking catalyst is a bifunctional catalyst, having simultaneously cracking activity and hydrogenation activity, i.e. containing simultaneously an acidic cracking component and a hydrogenation active component, wherein the acidic cracking component is generally selected from an acidic silica-alumina comprising a silica-alumina, a zeolite molecular sieve and a mixture thereof, while the hydrogenation active component is generally a metal selected from the group consisting of the VIB Group and VIII Group elements of the Periodic Table of Element, or an oxide and/or sulfide of the same. In order to meet with various requirements for the hydrocracked products, the acidic cracking component and the hydrogenation active component of the catalyst need to be modified as needed.
CN1054150C discloses a diesel oil hydrogenating conversion catalyst. The catalyst is composed of a carrier consisting of an alumina, an amorphous silica-alumina and a molecular sieve, and a hydrogenation-active metal supported on the carrier. The catalyst contains 10-30 wt % of WO3, 2-15 wt % of NiO, 5-45 wt % of a molecular sieve, 30-70 wt % of alumina, 5-25% of an amorphous silica-alumina. Said molecular sieve is a Y-molecular sieve having an infrared total acidity of 0.5-1 mmol/g, and a lattice constant of 2.436-2.444 nm. Said alumina is a small pore alumina with a pore volume of 0.8-1.1 ml/g and a surface area of 230-400 m2/g.
CN1184843A discloses a hydrogenating conversion catalyst for diesel oil, the catalyst has a composition of 40-80 wt % alumina, 0-20 wt % of an amorphous silica-alumina, 5-30 wt % of a molecular sieve, a VIB group metal content of 10-30 wt % and a V111 group metal oxide content of 2-15 wt %, wherein the molecular sieve is a Y-molecular sieve with a pore volume of 0.40-0.52 ml/g, a specific surface of 750-900 m2/g, a lattice constant of 2.420-2.500 and a silica/alumina ratio of 7-15.
U.S. Pat. No. 5,030,780 discloses a process for saturating aromatic compounds, wherein a catalyst containing a hydrogenation metal supported on a carrier is used. Said carrier contains a zeolite and a porous heat-resistant inorganic oxide, especially a heat-resistant inorganic oxide made of dispersing a silica-alumina in an alumina matrix, wherein the zeolite comprises various known crystallo-silica-alumina zeolites that are natural or synthetic, such as faujasite, mordenite, erionite zeolite, Y-zeolite, X-zeolite, L-zeolite, Ω-zeolite, ZSM-4-zeolite, Beta-zeolite and the like.
CN1055961C discloses a hydrocracking catalyst suitable for producing a middle fraction oil, containing an amorphous silica-alumina component and a small pore alumina adhesive, at least one element of the VIB group and at least one element of the VIII group, wherein the content of the amorphous silica-alumina is 30-60 wt %, the total content of the hydrogenation metal oxides is 20-35 wt % and the balance is the small pore alumina adhesive, characterized in that the catalyst has a specific surface of 150-300 m2/g, a pore volume of 0.25-0.50 ml/g, a distribution of the pore having a diameter of 4-15 nm in the range of 60-90% and an infrared acidity of 0.30-0.50 mmol/g.
CN1400284A discloses a catalyst for hydrotreating diesel oil. The catalyst contains a carrier, and molybdenum and/or tungsten and nickel and/or cobalt supported on the carrier, characterized in that the carrier is composed of alumina and a zeolite, with a weight-ratio of alumina to the zeolite in the range of 90:10-50:50, wherein the alumina is a complex of a small pore alumina and a large pore alumina in a weight-ratio of 75:25-50:50. The small pore alumina is one wherein the pore volume of the pore having a diameter less than 80 angstrom comprises more than 95% of the total pore volume, while the large pore alumina is one wherein the pore volume of the pore having a diameter of 60-600 angstrom comprises more than 70% of the total pore volume.
The hydrocracking catalysts provided according to the art can satisfy the requirements from some hydrocracking reactions, but a common problem shared by them is a lower conversion activity for aromatic hydrogenation.